Chern invariants of topological continua: A self-consistent nonlocal hydrodynamic model
Chern invariants of topological continua: A self-consistent nonlocal hydrodynamic model
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DOI：
10.1103/physrevb.105.035310
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发表时间：
2021-10
影响因子：
3.7
通讯作者：
S. Pakniyat;S. A. H. Gangaraj;G. Hanson
中科院分区：
文献类型：
--
作者：
S. Pakniyat;S. A. H. Gangaraj;G. Hanson
拓扑系统的特征是整数陈不变量。在以局部德鲁德模型为特征的连续光子系统中，材料响应在大波数下表现不佳，导致非整数陈省身不变量和拓扑边缘模式存在的模糊性。这个问题之前已经通过引入一个包含空间截止材料波数的特殊材料模型得到了解决，这导致了有限的布里渊区和整数不变量。在这项工作中，我们通过使用流体动力学德鲁德模型考虑非局域性的影响来计算磁化连续等离子体系统中的陈数。然后，我们认为该模型与以前的模型相比具有几个优点，例如引入大波数下的物理响应和总和为零的整数陈不变量，无需插值材料响应。因此，流体动力学模型形成了一个完整且自洽的模型，解决了拓扑光子连续体中的陈数问题。
Topological systems are characterized by integer Chern invarients. In a continuous photonic system characterized by a local Drude model, the material response is ill-behaved at large wavenumbers, leading to non-integer Chern invarients and ambiguity in the existence of topological edge modes. This problem has been solved previously by introducing an ad hoc material model including a spatial cutoff material’s wavenumber, which leads to a finite Brillouin zone and integer invarients. In this work, we calculate Chern numbers in magnetized continuous plasma systems by considering the effect of nonlocality using a hydrodynamic Drude model. Then, we argue that this model presents several advantages compared to the previous models, e.g. introducing physical response at large wave numbers and integer Chern invarients with sum to zero without the need for an interpolated material response. Therefore, the hydrodynamic model forms a complete and selfconsistent model, which resolves the Chern number issues in topological photonic continua.